Polysiloxanes containing amino groups are known as textile softeners (EP 441530). The introduction of amino structures modified by ethylene oxide/propylene oxide units as side chains causes an improvement of the effect (U.S. Pat. No. 5,591,880, U.S. Pat. No. 5,650,529). The alkylene oxide units permit in this case the selective setting of the hydrophilic-hydrophobic balance. Disadvantageous from the synthetic standpoint is the fact that, included in the synthesis strategy, there is the difficult esterification of amino alcohols with siloxane-bound carboxylic acid groups and, with respect to the softening properties, the general comb structure of the products.
To eliminate these disadvantage is has been proposed to convert α,ω-epoxymodified siloxanes with α,ω-aminofunctionalized alkylene oxides and to use these products as hydrophilic softeners (U.S. Pat. No. 5,807,956, U.S. Pat. No. 5,981,681).
To improve the substantivity, experiments were undertaken to introduce quaternary ammonium groups in alkylene oxide-modified siloxanes.
Branched alkylene oxide-modified polysiloxane quats have been synthesized from α,ω-OH terminated polysiloxanes and trialkoxysilanes by condensation. The quaternary ammonium structure is introduced via the silane, where the quaternary nitrogen atom is substituted with alkylene oxide units (U.S. Pat. No. 5,602,224).
Severe comb-like alkylene oxide-modified polysiloxane quats have also been described (U.S. Pat. No. 5,098,979). The hydroxyl groups of comb-like substituted polyether siloxanes are converted with epichlorohydrine into the corresponding chlorohydrine derivatives. Subsequently a quaternization is done with tertiary amines.
For this reason, the hydroxyl groups of comb-like substituted polyether siloxanes have been esterified alternatively with chloroacetic acid. Through the carbonyl activation the concluding quaternization can be completed in a simplified manner (U.S. Pat. No. 5,153,294, U.S. Pat. No. 5,166,297).
In U.S. Pat. No. 6,242,554 the α,ω-difunctional siloxane derivatives are described that each have a separate quaternary ammonium and alkylene oxide unit. These materials are distinguished by an improved compatibility with polar environments.
The reaction of α,ω-diepoxides with tertiary amines in the presence of acids provides α,ω-diquaternary siloxanes which can be used for the purposes of hair-grooming (DE-PS 3 719 086). Along with tetraalkyl-substituted quaternary ammonium structures, aromatic imidazolinium derivatives are also claimed.
A reduction of the ability to be washed out of the hair can be achieved if the α,ω-diepoxides are converted with ditertiary amines in the presence of acids into long-chain polyquaternary polysiloxanes (EP 282720).
Aromatic quaternary ammonium structures are not disclosed. Derivatives of this type are treated in U.S. Pat. No. 6,240,929. In a first step two diamines having two imidazole units are synthesized from imidazole and suitable difunctional alkylation agents, said diamines subsequently being converted into polyquaternary polysiloxanes in a manner analogous to EP 282720. Cationic compounds produced in this way should have a further increased compatibility with respect to the anionic surfactants present in cosmetic formulations. However, the resistance to being washed out of the hair relates to short-term attack of primarily water and very mild surfactants not irritating the skin while wash-resistant, hydrophilic softeners for textiles have to withstand the attack of concentrated surfactant solutions with high fat-dissolving and dirt-dissolving power. Making it more difficult in addition is the fact that modern detergents contain strongly alkaline complex promoters, oxidatively acting bleaches, and complex enzyme systems, with the fibers often being exposed to the action for hours at elevated temperatures.
Alternative approaches to the improvement of the compatibility with anionic surfactant systems or the efficiency of the siloxane deposition on surfaces are targeted at the use of greater amounts of cationic surfactants (WO 00-71806 and WO 00-71807) or the utilization of cationic polysaccharide derivatives (J. V. Gruber et al., Colloids and Surfaces B; Biointerfaces 19 (2000), 127-135) in mixtures with polydimethyl siloxanes.
Highly charged, very hydrophilic synthetic polycationics are also in the position to improve the compatibility with anionic surfactant systems (U.S. Pat. No. 6,211,139) or in the presence of solutions of anionic surfactants to associate with fibers (WO 99-14300). In the latter document, polyimidazolinium derivatives, among others, are described.
None of the proposals treated represents a satisfactory solution to the problem of obtaining the soft feel possible through silicone and the pronounced hydrophily after initial finishing of a textile material even when it is exposed to attack of aggressive detergent formulations, that is, among others, detergent formulations with a high pH value (>10) and highly active surfactants in the course of repeated washing processes at, in given cases, an elevated temperature.
A fundamentally different approach is described in DE-OS 3 236 466. The conversion of OH-terminated siloxanes with alkoxysilanes containing quaternary ammonium structures provides reactive intermediate products which are supposed to be cross-linked with suitable cross-linking agents, such as trialkoxysilanes, on the fiber surface to form wash-resistant layers. A decisive disadvantage of this approach is the fact that the necessary hours-long stability of an aqueous finishing bath cannot be guaranteed and unforeseen cross-linking reactions in the batch can already occur before the textile finishing.
Self-cross-linking emulsions of aminosiloxanes are also known (U.S. Pat. No. 4,661,577). For this, trialkoxysilyl structures terminal in the molecule are introduced.
A cross-linking of aminosiloxanes can also be achieved by reaction with epichlorohydrine or diepoxides (WO 01-27232) or, analogous to Michael addition, by a reaction with diacrylates (DE 198 03 468).
Alternative approaches with the participation of cross-linked structures deal with, among other things, mixtures of hydrocarbon-based quats (compounds containing quaternary ammonium groups) and cross-linked siloxanes (U.S. Pat. No. 4,908,140) or the additional incorporation of straight-chain siloxanes (U.S. Pat. No. 4,978,462).
WO 02-10257 describes linear polysiloxane compounds which contain polyalkylene oxide structural units, ammonium groups, and polysiloxane structural units in which the possibility of a branching is in fact mentioned but no branched polysiloxane compounds or actual branching components needed to build them are described. The mentioned multi-functional groups thus do not serve for building branches but rather the saturation within the linear main chain or for building monofunctional side chains.
These linear polysiloxane compounds, however, still always have disadvantages with regard to their substantivity.
Branched polysiloxane compounds were previously considered by those skilled in the art as unsuitable to serve as soluble or emulsifiable, i.e., applicable, softeners because they incline toward-the formation of highly molecular gels so that they cannot be applied to the fibers from aqueous solution.
It was thus completely surprising that the special, branched polysiloxane polymers, as they were prepared for the first time by the inventors of the present patent application, were, on the one hand, soluble and applicable and have, at the same time, a higher substantivity (durability), and even in many cases an increased softening action, with respect to the linear polysiloxane compounds.
The hydrophilic, polyquaternary polysiloxane copolymers according to the invention can thus lend textiles, after appropriate application, a soft feel typical of silicone and a pronounced hydrophilicity, and this profile of properties is also not lost after the action of detergent formulations during repeated washing processes at, in given cases, an elevated temperature.
Furthermore, the hydrophilic, polyquaternary polysiloxane copolymers according to the invention can serve as separate softeners or as softeners in formulations for washing fibers and textiles which are based on non-ionogenic or anionic/non-ionogenic surfactants as well as an aid to ironing and means for preventing or reversing creases in textiles.